The First Flight Pt.II

January 2, 2011

Work is really a mutual thing- I mean, the work and me. I’m glad I needed to work and the work needed me. So I’m also part of our modeling group. I know other teams mostly use CATIA. But we chose Inventor. With limited experience with this software, I was bold enough to deal with internal structure of wings.

Again, it was all blank in my database when it comes to internal structure. Neo briefed me that wing ribs, beams should be included; control surfaces should be split from the original wing surface, in order to move it in assembly mode. But how thick is a single wing rib? How distant is it between two ribs? What about the beams? And all those technical problems using the software… Ideally, a modeling group member should be spared asking such questions, as detailed parameters should be given before drawing begins. Unfortunately we’re a small team, we had to feed ourselves by looking for them on our own. It took me quite a while to get used to the instruction system of Inventor 2010. And the questions I raised to myself were all resolved by referring to the handbook. Thankfully, a lot of books out there concerning the wing structure are pretty convincing. Really have learnt a lot all the way down.

A story worth mentioning here is about the wing ribs. The front wing of our aircraft has a sweepback of 37 degrees. Initially Neo said the ribs were parallel to the airflow. While I thought it should be positioned perpendicular to the trailing edge, with James on my side. The great news was Aircraft Design Handbook has a whole chapter addressing this issue. I came to know that actually both layouts are seen in aircraft structure design. The former ensures a smoother wing surface in flight, but is heavier; the latter is more widely employed, the main advantage is that it’s lighter. With this in mind, the final layout was changed.

There do exist some tragic incidents, which I prefer not to put in detail 🙁 One of them is related to lack of experience with Inventor. The features I created on the aft wing were such a mess that it became impossible to modify in the end.’doh! A good planning before starting to draw is so important. This is the lesson I learnt. Then afterwards, I tackled the front wing, which was a little more complex than the aft wing, I finished it in two hours and got infinite praise from Neo, thanks to the conscious mentality this time. Yummy!

Other parts I did include landing gear and cargo container assembly. Genuinely a great sense of accomplishment when seeing the meat of our teamwork rotating on the screen before us. And as the final round is about to strike, I completed my part of report about seating/cabin door/cargo container arrangement, fuselage design and nacelle design.

It’s now time to address some non-technical problems here.

It keeps occurring that there are conflicting numbers regarding the same parameter. For example I was the one to set the seating capacity at 248, but to the group leader’s knowledge it was 247 and someone else has another version. No wonder in our presentation, the relative thickness of a NACA0012 airfoil could be stated as 8%. Poor data management creates confusion; and confusion creates frustration.

Another haunting problem is about the coursework itself. I’m not sure how precise we have to make it. There are certain limits of what we can do, while some, though not all questions raised by teachers implied mission impossible.

Moreover, sometimes it makes me blind when people say we’ve got to do a cool video, a cool presentation and some stuffs like that. I know these are essential to win the competition, but I never quite get a balancing point.

But again, what a road! It feels unbelievable how much I did and learnt. I’ve experienced the design process, full of paradoxes, conflicts while filled with joy, through playing multiple roles. It was great fun working with a bunch of guys generally named “awesome”. Peace :]

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